1. Technical Field
The disclosure relates to a clutch apparatus of a transmission for a vehicle.
2. Description of Related Art
A clutch drum provided in an automatic transmission for a vehicle attempts to expand radially outward due to a centrifugal force generated by the rotation of the clutch drum or due to a radially outward load generated by the transmission of torque. Japanese Patent Application Publication No. 2012-219976 (JP 2012-219976 A) describes a clutch drum provided with an annular band. The annular band is provided on an outer peripheral portion of the clutch drum in order to restrain the clutch drum from expanding radially outward.
A band may be made of a resin material in order to increase the rigidity of a clutch drum and to achieve weight reduction of the clutch drum. However, a clutch drum made of metal and a band made of resin are different in coefficient of thermal expansion from each other. For this reason, when a band is made of a resin material, a clearance may be formed between a clutch drum and the band in the radial direction due to temperature changes. As a result, the band is displaced with respect to the clutch drum, and thus the band may be detached from the clutch drum. To be specific, when a clutch drum made of metal shrinks but a band made of carbon fiber reinforced plastic (CFRP) does not shrink under a low-temperature environment, the band may be detached from the clutch drum as described above.